"Each winter, as the waters of Botswana’s Okavango River spread across its vast delta, an array of African wildlife congregates to eat, drink, splash, and soak. This seasonal wetland was especially important in 2019, when severe drought left human and animal populations alike desperate for water. Cattle, elephants, crocodiles, and other creatures were left to vie for any water they could find in the delta’s shrinking pools.

Among those seeking refuge were herds of hippopotamuses (Hippopotamus amphibious). These semi-aquatic herbivores are well-equipped for spending hours each day in the water—their nostrils and eyes located so high on their head that they can breathe and see while mostly submerged. They’re also graceful swimmers, and can hold their breath for up to five minutes. But even their aquatic abilities and impressive heft were no match for last year’s muddy, drought-stricken delta. At least 200 hippos became trapped in the mud, and managed to survive only because Botswana wildlife officials pumped in water to help them escape. As the climate warms, such droughts may become more frequent across much of Africa."